Currently, The National Institutes of Health, the Centers for Disease Control and Prevention and the HIV (Human Immunodeficiency Virus) Medicine Association of the Infectious Diseases Society of America guidelines state that prophylaxis against Pneumocystis jirovecii pneumonia (PCP) may be discontinued safely in HIV-infected individuals when CD4 counts are maintained >200 cells/μL for over three months on antiretroviral therapy [1]. This evidence concerns the gene CD4 and pneumocystosis.